Lustre 1.6 Operations Manual

19.3 PIOS Test Tool
The PIOS test tool is a parallel I/O simulator for Linux and Solaris. PIOS generates
I/O on filesystems, block devices and zpools similar to what can be expected from a
large Lustre OSS server when handling the load from many clients. The program
generates and executes the I/O load in a manner substantially similar to an OSS,
that is, multiple threads take work items from a simulated request queue. It forks a
CPU load generator to simulate running on a system with additional load.
PIOS can read/write data to a single shared file or multiple files (default is a single
file). To specify multiple files, use the --fpp option. (It is better to measure with both
single and multiple files.) If the final argument is a file, block device or zpool, PIOS
writes to RegionCount regions in one file. PIOS issues I/O commands of size
ChunkSize. The regions are spaced apart Offset bytes (or, in the case of many files,
the region starts at Offset bytes). In each region, RegionSize bytes are written or
read, one ChunkSize I/O at a time. Note that:
ChunkSize